Jintsuu's cosplayer appears to have deleted their account at some point. The other two are tagged in the post as well as mentioned, but sumire_maru is only mentioned. There is a live 2021 account with that handle, but can't be sure it's the cosplayer.
Edit: They left a reply on the tweet for post #9939. Their original account is still live just renamed.
Note, for this set, the live @ points to a 2023 account that does not appear to be the original cosplayer. The plaintext @ is a former handle of 99tkmo, as they are still tagged in the post and left a reply.
The mentioned twitter account matches an artist with a danbooru entry, but I don't know if it's actually the same person since all their tweets have been deleted.
No idea who the cosplayers are on a lot of these. Only a few have @s mentioned, fewer of those are still live accounts. im making entries for everything that mentions a live account (this one does have replies from an account, its just private and i didnt notice its there, and i can't be sure it's one of the cosplayers in the image from the context)
